A trocar assembly for use in endoscopic surgical procedures generally comprises two major components, a trocar obturator and a tube or cannula. Typically, the obturator is initially positioned within the cannula and has a sharp and pointed puncturing tip which is extendable from the cannula. The obturator tip is used to penetrate the skin and underlying tissue to provide cannula access to a body cavity. The obturator is then removed and endoscopic surgery performed through the cannula.
Many trocars have safety shields which can cover the tip of the obturator. If the trocar is disarmed, the safety shield is maintained in its tip covering position. When the trocar assembly is engaged for puncturing, the safety shield can be moved to expose the puncturing tip. A user then applies a force to the trocar and the obturator is used to puncture skin and tissue to reach the location for surgery. When the force is released, the safety shield re-covers the obturator tip.
It requires a mechanical force to puncture the skin and muscles to reach soft tissue, typically the desired location for surgery. In abdominal surgery, for example, the abdominal wall which comprises epidermal layers, fascia, muscle and peritoneum is punctured to reach internal viscera. Frequently when the soft tissue is reached, there is a sudden release in resistance to the puncturing force, at which point the user releases the force to avoid undesired puncturing of other tissue with the sharp obturator point as the safety shield covers the obturator tip.
It is therefore an object of this invention to provide a trocar which further reduces any risk of injury to soft or underlying tissue, from a puncturing obturator tip. It is also an object of the invention to provide a trocar which assists the user in puncturing tissue, thereby reducing the necessary amount of user force and enabling greater and easier user control. It is another object of the invention to provide a trocar which would not require a safety shield.